1. Field of the Invention
The present invention relates to a cable type steering system in which a steering wheel and a steering gear box are connected to each other with flexible operation cables such as a Bowden cable. More particularly, the present invention relates to a cable type steering system wherein a detent portion formed on an outer circumference of a pulley boss is visible even when using molded drive pulley and driven pulley main bodies.
2. Description of the Related Art
The cable type steering system is disclosed in, for example, JP-A-2000-25623, JP-A-10-59197 and JP-A-8-2431.
In this type of cable type steering system, even in a case where a drive pulley main body and a driven pulley main body are made of a synthetic resin in order to reduce the weight of the steering system, a pulley boss constituting a rotating shaft thereof needs to be made of a metal due to the reason for ensuring a required strength. In this case, it is contemplated to rigidly integrate a pulley main body made of a synthetic resin onto an outer circumference of the metallic pulley boss and to integrally mold a pulley main body of a synthetic resin in such a manner as to cover a detent portion formed on the outer circumference of a boss portion from an axial direction and a radial direction in order to prevent the generation of looseness.
In the event that the pulley main body of a synthetic resin is integrally molded over the outer circumference of the metallic pulley boss as has been described above, if no detent portion is formed on the outer circumference of the pulley boss due to a processing error, there is caused a concern that when a large magnitude of steering torque is applied thereto, the steering torque is not sufficiently transmitted. However, there is caused a problem that once the pulley boss is covered with the pulley main body, the condition of the detent portion on the pulley boss cannot be confirmed from the outside of the pulley main body.
The invention was made in view of the above situation, and an object thereof is to provide a cable type steering system in which one can surely confirm the condition of a detent portion on a pulley boss which is covered with a pulley main body of a cable type steering system.
With a view to attaining the object, according to a first aspect of the invention, there is provided a cable type steering system in which a drive pulley coupled to a steering wheel for rotation and a driven pulley coupled to a steering gear box for steering wheels for rotation are connected by operation cables so that a steering torque inputted to the steering wheel is transmitted to the steering gear box via the operation cables. The cable type steering system of this first aspect is characterized in that at least one of a drive pulley main body and a driven pulley main body is molded of a synthetic resin in such a manner as to cover detent portion(s) formed on outer circumference(s) of associated pulley boss(es) made of, for example, metal both from an axial direction and a radial direction, and in that at least part of the covered detent portion(s) can be visualized from outside of the covering pulley main body.
According to the construction, since at least part of the detent portions formed on the outer circumferences of the metallic pulley bosses can be visualized from the outside of the drive pulley main body or the driven pulley main body which is molded of the synthetic resin in such a manner as to cover the detent portions, it is possible to ensure confirmation of any absence of formation of a detent portion on the pulley boss due to a processing error.
According to a second aspect of the invention, there is provided a cable type steering system as set forth in the first aspect of the invention, wherein at least part of the detent portions can be visualized through recessed portions formed for fixing end portions of the operation cables to the drive pulley main body or the driven pulley main body.
According to the construction, since part of the detent portions can be visualized through the recessed portions formed for fixing the end portions of the operation cables to the drive pulley main body or the driven pulley main body, it is possible to ensure confirmation of existence of the detent portions on the pulley bosses without implementing any particular or extra processing to the pulley main bodies.
Note that serrated portions 33a, 71a in an embodiment correspond to the detent portions of the invention and pin holes 34a, 77a in the embodiment correspond to the recessed portions of the invention.